<?php
namespace Com;
/**
 * Shopping Cart Class
 */
class Cart {
	
	// These are the regular expression rules that we use to validate the product ID and product name
	var $product_id_rules = '\.a-z0-9_-'; // alpha-numeric, dashes, underscores, or periods
	var $product_name_rules = '\.\:\-_ a-z0-9'; // alpha-numeric, dashes, underscores, colons or periods
	                                            
	// Private variables. Do not change!
	var $_cart_contents = array ();

	/**
	 * Shopping Class Constructor
	 *
	 * The constructor loads the Session class, used to store the shopping cart contents.
	 */
	public function __construct($params = array()) {
		// Are any config settings being passed manually? If so, set them
		$config = array ();
		if (count ( $params ) > 0) {
			foreach ( $params as $key => $val ) {
				$config [$key] = $val;
			}
		}
		
		// Grab the shopping cart array from the session table, if it exists
		if (session ( 'cart_contents' ) !== null) {
			$this->_cart_contents = session ( 'cart_contents' );
		} else {
			// No cart exists so we'll set some base values
			$this->_cart_contents ['cart_total'] = 0;
			$this->_cart_contents ['total_items'] = 0;
		}
		
		//Log::record ( 'Cart Class Initialized', Log::DEBUG );
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Insert items into the cart and save it to the session table
	 *
	 * @access public
	 * @param
	 *        	array
	 * @return bool
	 */
	function insert($items = array()) {
		// Was any cart data passed? No? Bah...
		if (! is_array ( $items ) or count ( $items ) == 0) {
			Log::record ( 'The insert method must be passed an array containing data.', Log::ERR );
			return FALSE;
		}
		
		// You can either insert a single product using a one-dimensional array,
		// or multiple products using a multi-dimensional one. The way we
		// determine the array type is by looking for a required array key named "id"
		// at the top level. If it's not found, we will assume it's a multi-dimensional array.
		
		$save_cart = FALSE;
		if (isset ( $items ['id'] )) {
			if (($rowid = $this->_insert ( $items ))) {
				$save_cart = TRUE;
			}
		} else {
			foreach ( $items as $val ) {
				if (is_array ( $val ) and isset ( $val ['id'] )) {
					if ($this->_insert ( $val )) {
						$save_cart = TRUE;
					}
				}
			}
		}
		// Save the cart data if the insert was successful
		if ($save_cart == TRUE) {
			$this->_save_cart ();
			return isset ( $rowid ) ? $rowid : TRUE;
		}
		
		return FALSE;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Insert
	 *
	 * @access private
	 * @param
	 *        	array
	 * @return bool
	 */
	function _insert($items = array()) {
		// Was any cart data passed? No? Bah...
		if (! is_array ( $items ) or count ( $items ) == 0) {
			Log::record ( 'The insert method must be passed an array containing data.', Log::ERR );
			return FALSE;
		}
		
		// --------------------------------------------------------------------
		
		// Does the $items array contain an id, quantity, price, and name? These are required
		if (! isset ( $items ['id'] ) or ! isset ( $items ['qty'] ) or ! isset ( $items ['price'] ) or ! isset ( $items ['name'] )) {
			Log::record ( 'The cart array must contain a product ID, quantity, price, and name.', Log::ERR );
			return FALSE;
		}
		
		// --------------------------------------------------------------------
		
		// Prep the quantity. It can only be a number. Duh...
		$items ['qty'] = trim ( preg_replace ( '/([^0-9])/i', '', $items ['qty'] ) );
		// Trim any leading zeros
		$items ['qty'] = trim ( preg_replace ( '/(^[0]+)/i', '', $items ['qty'] ) );
		
		// If the quantity is zero or blank there's nothing for us to do
		if (! is_numeric ( $items ['qty'] ) or $items ['qty'] == 0) {
			return FALSE;
		}
		
		// --------------------------------------------------------------------
		
		// Validate the product ID. It can only be alpha-numeric, dashes, underscores or periods
		// Not totally sure we should impose this rule, but it seems prudent to standardize IDs.
		// Note: These can be user-specified by setting the $this->product_id_rules variable.
		if (! preg_match ( "/^[" . $this->product_id_rules . "]+$/i", $items ['id'] )) {
			Log::record ( 'Invalid product ID.  The product ID can only contain alpha-numeric characters, dashes, and underscores', Log::ERR );
			return FALSE;
		}
		
		// --------------------------------------------------------------------
		
		// Validate the product name. It can only be alpha-numeric, dashes, underscores, colons or periods.
		// Note: These can be user-specified by setting the $this->product_name_rules variable.
		/* if (! preg_match ( "/^[" . $this->product_name_rules . "]+$/i", $items ['name'] )) {
			Log::record ( 'An invalid name was submitted as the product name: ' . $items ['name'] . ' The name can only contain alpha-numeric characters, dashes, underscores, colons, and spaces', Log::ERR );
			return FALSE;
		} */
		
		// --------------------------------------------------------------------
		
		// Prep the price. Remove anything that isn't a number or decimal point.
		$items ['price'] = trim ( preg_replace ( '/([^0-9\.])/i', '', $items ['price'] ) );
		// Trim any leading zeros
		$items ['price'] = trim ( preg_replace ( '/(^[0]+)/i', '', $items ['price'] ) );
		
		// Is the price a valid number?
		if (! is_numeric ( $items ['price'] )) {
			Log::record ( 'An invalid price was submitted for product ID: ' . $items ['id'], Log::ERR );
			return FALSE;
		}
		
		// --------------------------------------------------------------------
		
		// We now need to create a unique identifier for the item being inserted into the cart.
		// Every time something is added to the cart it is stored in the master cart array.
		// Each row in the cart array, however, must have a unique index that identifies not only
		// a particular product, but makes it possible to store identical products with different options.
		// For example, what if someone buys two identical t-shirts (same product ID), but in
		// different sizes? The product ID (and other attributes, like the name) will be identical for
		// both sizes because it's the same shirt. The only difference will be the size.
		// Internally, we need to treat identical submissions, but with different options, as a unique product.
		// Our solution is to convert the options array to a string and MD5 it along with the product ID.
		// This becomes the unique "row ID"
		if (isset ( $items ['options'] ) and count ( $items ['options'] ) > 0) {
			$rowid = md5 ( $items ['id'] . implode ( '', $items ['options'] ) );
		} else {
			// No options were submitted so we simply MD5 the product ID.
			// Technically, we don't need to MD5 the ID in this case, but it makes
			// sense to standardize the format of array indexes for both conditions
			$rowid = md5 ( $items ['id'] );
		}
		
		// --------------------------------------------------------------------
		
		// Now that we have our unique "row ID", we'll add our cart items to the master array
		
		// let's unset this first, just to make sure our index contains only the data from this submission
		unset ( $this->_cart_contents [$rowid] );
		
		// Create a new index with our new row ID
		$this->_cart_contents [$rowid] ['rowid'] = $rowid;
		
		// And add the new items to the cart array
		foreach ( $items as $key => $val ) {
			$this->_cart_contents [$rowid] [$key] = $val;
		}
		
		// Woot!
		return $rowid;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Update the cart
	 *
	 * This function permits the quantity of a given item to be changed.
	 * Typically it is called from the "view cart" page if a user makes
	 * changes to the quantity before checkout. That array must contain the
	 * product ID and quantity for each item.
	 *
	 * @access public
	 * @param
	 *        	array
	 * @param
	 *        	string
	 * @return bool
	 */
	function update($items = array()) {
		// Was any cart data passed?
		if (! is_array ( $items ) or count ( $items ) == 0) {
			return FALSE;
		}
		
		// You can either update a single product using a one-dimensional array,
		// or multiple products using a multi-dimensional one. The way we
		// determine the array type is by looking for a required array key named "id".
		// If it's not found we assume it's a multi-dimensional array
		$save_cart = FALSE;
		if (isset ( $items ['rowid'] ) and isset ( $items ['qty'] )) {
			if ($this->_update ( $items ) == TRUE) {
				$save_cart = TRUE;
			}
		} else {
			foreach ( $items as $val ) {
				if (is_array ( $val ) and isset ( $val ['rowid'] ) and isset ( $val ['qty'] )) {
					if ($this->_update ( $val ) == TRUE) {
						$save_cart = TRUE;
					}
				}
			}
		}
		
		// Save the cart data if the insert was successful
		if ($save_cart == TRUE) {
			$this->_save_cart ();
			return TRUE;
		}
		
		return FALSE;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Update the cart
	 *
	 * This function permits the quantity of a given item to be changed.
	 * Typically it is called from the "view cart" page if a user makes
	 * changes to the quantity before checkout. That array must contain the
	 * product ID and quantity for each item.
	 *
	 * @access private
	 * @param
	 *        	array
	 * @return bool
	 */
	function _update($items = array()) {
		// Without these array indexes there is nothing we can do
		if (! isset ( $items ['qty'] ) or ! isset ( $items ['rowid'] ) or ! isset ( $this->_cart_contents [$items ['rowid']] )) {
			return FALSE;
		}
		
		// Prep the quantity
		$items ['qty'] = preg_replace ( '/([^0-9])/i', '', $items ['qty'] );
		
		// Is the quantity a number?
		if (! is_numeric ( $items ['qty'] )) {
			return FALSE;
		}
		
		// Is the new quantity different than what is already saved in the cart?
		// If it's the same there's nothing to do
		if ($this->_cart_contents [$items ['rowid']] ['qty'] == $items ['qty']) {
			return FALSE;
		}
		
		// Is the quantity zero? If so we will remove the item from the cart.
		// If the quantity is greater than zero we are updating
		if ($items ['qty'] == 0) {
			unset ( $this->_cart_contents [$items ['rowid']] );
		} else {
			$this->_cart_contents [$items ['rowid']] ['qty'] = $items ['qty'];
		}
		
		return TRUE;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Save the cart array to the session DB
	 *
	 * @access private
	 * @return bool
	 */
	function _save_cart() {
		// Unset these so our total can be calculated correctly below
		unset ( $this->_cart_contents ['total_items'] );
		unset ( $this->_cart_contents ['cart_total'] );
		
		// Lets add up the individual prices and set the cart sub-total
		$total = 0;
		$items = 0;
		foreach ( $this->_cart_contents as $key => $val ) {
			// We make sure the array contains the proper indexes
			if (! is_array ( $val ) or ! isset ( $val ['price'] ) or ! isset ( $val ['qty'] )) {
				continue;
			}
			
			$total += ($val ['price'] * $val ['qty']);
			$items += $val ['qty'];
			
			// Set the subtotal
			$this->_cart_contents [$key] ['subtotal'] = ($this->_cart_contents [$key] ['price'] * $this->_cart_contents [$key] ['qty']);
		}
		
		// Set the cart total and total items.
		$this->_cart_contents ['total_items'] = $items;
		$this->_cart_contents ['cart_total'] = $total;
		
		// Is our cart empty? If so we delete it from the session
		if (count ( $this->_cart_contents ) <= 2) {
			session ( 'cart_contents', NULL );
			
			// Nothing more to do... coffee time!
			return FALSE;
		}
		
		// If we made it this far it means that our cart has data.
		// Let's pass it to the Session class so it can be stored
		session ( 'cart_contents', $this->_cart_contents );
		
		// Woot!
		return TRUE;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Cart Total
	 *
	 * @access public
	 * @return integer
	 */
	function total() {
		return $this->_cart_contents ['cart_total'];
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Total Items
	 *
	 * Returns the total item count
	 *
	 * @access public
	 * @return integer
	 */
	function total_items() {
		return $this->_cart_contents ['total_items'];
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Cart Contents
	 *
	 * Returns the entire cart array
	 *
	 * @access public
	 * @return array
	 */
	function contents() {
		$cart = $this->_cart_contents;
		
		// Remove these so they don't create a problem when showing the cart table
		unset ( $cart ['total_items'] );
		unset ( $cart ['cart_total'] );
		
		return $cart;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Has options
	 *
	 * Returns TRUE if the rowid passed to this function correlates to an item
	 * that has options associated with it.
	 *
	 * @access public
	 * @return array
	 */
	function has_options($rowid = '') {
		if (! isset ( $this->_cart_contents [$rowid] ['options'] ) or count ( $this->_cart_contents [$rowid] ['options'] ) === 0) {
			return FALSE;
		}
		
		return TRUE;
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Product options
	 *
	 * Returns the an array of options, for a particular product row ID
	 *
	 * @access public
	 * @return array
	 */
	function product_options($rowid = '') {
		if (! isset ( $this->_cart_contents [$rowid] ['options'] )) {
			return array ();
		}
		
		return $this->_cart_contents [$rowid] ['options'];
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Format Number
	 *
	 * Returns the supplied number with commas and a decimal point.
	 *
	 * @access public
	 * @return integer
	 */
	function format_number($n = '') {
		if ($n == '') {
			return '';
		}
		
		// Remove anything that isn't a number or decimal point.
		$n = trim ( preg_replace ( '/([^0-9\.])/i', '', $n ) );
		
		return number_format ( $n, 2, '.', ',' );
	}
	
	// --------------------------------------------------------------------
	
	/**
	 * Destroy the cart
	 *
	 * Empties the cart and kills the session
	 *
	 * @access public
	 * @return null
	 */
	function destroy() {
		unset ( $this->_cart_contents );
		
		$this->_cart_contents ['cart_total'] = 0;
		$this->_cart_contents ['total_items'] = 0;
		
		session ( 'cart_contents', NULL );
	}
}
// END Cart Class

/* End of file Cart.php */